Vehicle tires serve to transmit all the forces and torques between the vehicle and the roadway. For this reason, monitoring or checking of the tires permits vehicle regulating systems to be set better and, if appropriate, hazardous situations to be detected.
For this purpose it is known, on the one hand, to measure and to monitor the air pressure in vehicle tires. Furthermore, wear sensors are known that, if appropriate, can contribute to detecting a hazardous situation in the case of excessive wear of the tire profile.
DE 101 19 352 C1 describes a method for determining the profile properties of a vehicle tire, wherein microwaves are emitted by close-range radar sensors assigned to the tires, and the profile depth of the vehicle tires can therefore be determined.
DE 100 58 099 A1 describes a method and a device for detecting or estimating abrasion of a tire, in which vehicle movement dynamics variables and other measurement variables that influence the abrasion of the tire are sensed during the normal operation of a vehicle by driving state sensors of the vehicle regulating systems using sensor signals, and the variables are stored and evaluated for approximate detection of the tire state or tire wear.
WO 2009/089972 A1 describes a method for distributing the driving torque among the wheels of a vehicle as a function of the tire state. In this context, tires with low air pressure can be detected automatically by means of air pressure sensors or else on the basis of the wheel speeds. Furthermore, the wear or the profile depth of the individual wheels can be determined by means of a sensor system.
EP 1 549 536 B1 describes improvements of the vehicle stability control, wherein tire force properties are included. In this context, the pressure of a tire is determined by means of a sensor, from which tire forces can be estimated and information about the reaction of the vehicle to a driver input can be estimated, in order to determine an active correction for the wheel lock angle, the braking torque and/or a driving torque.
Furthermore, spectroscopic sensors are known with which surfaces can be detected. Such spectroscopic sensors can also be used from a vehicle.